Jazz-loving, woodship teacher Trevor Chaplin and his girlfriend Jill are on the trail of a saleswoman who mistakenly delivered a set of records that were supposed to be by Bix Beiderbecke.

Jill is detained by the police, Trevor goes in pursuit of a platinum blonde, Big Al reveals some of his secrets, and Sergeant Hobson tries to make sense of it all.

Trevor has succeeded in finding the music he's been looking for and Jill's campaign is reaching fever pitch. But who is the mysterious supergrass and the woman 'with a past'? Will the truth ever be revealed to Det Sgt Hobson?

Trevor is at the apex of an emotional triangle, Sergeant Hobson is in trouble, and Jill is taken out to dinner.

Jill and Trevor have an emotional crisis, Sergeant Hobson has a policing crisis, and Big Al has a storage crisis. But the question on everybody's mind is: 'Who is McAllister?'.

Somehow, a bizarre twist of fate plunges the couple into a mystery involving bureaucracy and death threats. All is revealed in this final episode: will Hobson find fame and glory, will Trevor and Jill find true happiness, and will Mr Carter ever really understand his two teaching colleagues?

Trevor Chaplin teaches woodwork and likes to listen to jazz. Jill Swinburne teaches English and wants to help save the planet. They live together and just want a quiet life. Then they meet John the barman who died but is much better now. John gave them a tape which led to meeting Dave the wimp. They find out about The Peoples Front For The Liberation of west Yorkshire. The man with no name called Mr Peterson came to see them. He was followed by the six men in grey suits. Jill goes to see The Oldest Suffragette In Town. Trevor and Jill go on a trip to Amsterdam with their class from "San Quentin High". Trevor and Jill meet The Honourable Order of Elks who are "looking for a bit of action"

Trevor Chaplin teaches woodwork and likes to listen to jazz. Jill Swinburne teaches English and wants to help save the planet. They live together and just want a quiet life. Then they meet John the barman who died but is much better now. John gave them a tape which led to meeting Dave the wimp. They find out about The Peoples Front For The Liberation of west Yorkshire. The man with no name called Mr Peterson came to see them. He was followed by the six men in grey suits. Jill goes to see The Oldest Suffragette In Town. Trevor and Jill go on a trip to Amsterdam with their class from "San Quentin High". Trevor and Jill meet The Honourable Order of Elks who are "looking for a bit of action".